A narrow waveguide 650 nm semiconductor laser device and a preparation method thereof

Abstract

The application relates to a narrow waveguide 650nm semiconductor laser device and a preparation method thereof. 1‑x5 In x5 Psecond quantum well and (Al x7 Ga 1‑x7 ) y5 In 1‑y5 Pupper waveguide layer are arranged with low-refractive-index (Al x6 Ga 1‑x6 ) y4 In 1‑y4 Pbarrier layer, tensile strain compensation is adopted to reduce the refractive index of the barrier, promote light field expansion, and reduce the far-field beam divergence angle; meanwhile, (Al x7 Ga 1‑x7 ) y5 In 1‑y5 Pupper waveguide layer and (Al 1‑x1 Ga x1 ) y1 In 1‑y1 Plower waveguide layer adopts a narrow waveguide structure to reduce light field restriction capability, expand the vertical direction light field, and reduce the far-field divergence angle.

Description

Technical Field

[0001] This invention relates to a narrow waveguide 650nm semiconductor laser device and its fabrication method, belonging to the field of optoelectronic technology. Background Technology

[0002] Semiconductor lasers have outstanding advantages such as small size, light weight, low cost, high efficiency, long life, easy modulation and wide wavelength coverage. Among them, 650nm semiconductor lasers have broad application prospects in medical aesthetics, laser display and industrial measurement. However, the large vertical divergence angle, relatively low single tube power and poor lateral beam quality of traditional semiconductor lasers limit the further application of 650nm semiconductor lasers.

[0003] To ensure fundamental mode operation, traditional semiconductor lasers typically employ thin waveguides during epitaxial growth, resulting in a large vertical divergence angle. This significantly impacts the coupling efficiency between the semiconductor laser and optical fiber, increases coupling difficulty and cost, and also makes the small emitting area and high surface area power density susceptible to catastrophic surface damage and slow degradation. Therefore, reducing the vertical divergence angle of semiconductor lasers can improve both their coupling efficiency with optical fiber and the power per unit of the device.

[0004] Chinese invention patent CN104300365A discloses a method for fabricating a laser that simultaneously reduces divergence angle and threshold current. This method introduces an asymmetrically doped low-refractive-index layer between the waveguide layer and the confinement layer, creating an anti-waveguide effect. This anti-waveguide effect, along with the active region and the waveguide layer, modulates the distribution of the optical field in the laser, thereby altering the optical confinement factor of the active region and ultimately affecting the laser's threshold current and vertical divergence angle. However, 650nm lasers typically use AlInP as the confinement layer, which has the lowest refractive index among AlGaInP materials, making it impossible to insert an even lower refractive-index layer between the AlInP confinement layer and the AlGaInP waveguide layer.

[0005] Chinese invention patent CN106532433A discloses a laser with a narrow vertical far-field divergence angle and its fabrication method. By increasing the thickness of the active region and using a large optical cavity, the far-field divergence angle is reduced. Simultaneously, a tensile strain confinement layer is used to increase the refractive index, extending the optical field into the outer confinement layer. This strain-based extension of the vertical optical field further reduces the far-field divergence angle. However, if a tensile strained AlInP laser is used as the confinement layer, a small refractive index difference when the strain is small makes it difficult to generate optical field shift. Conversely, a large strain can lead to strain accumulation, causing defects such as dislocations and deteriorating operational reliability. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a narrow waveguide 650nm semiconductor laser device and its fabrication method. By inserting a low-refractive-index barrier layer between the waveguide layer and the quantum well, and employing tensile strain compensation, the refractive index of the barrier is reduced, promoting optical field expansion and reducing the far-field beam divergence angle. By using a narrow waveguide structure, the optical field confinement capability is reduced, the vertical optical field is expanded, and the far-field divergence angle is reduced.

[0007] The technical solution of this invention is as follows: A narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer includes, from bottom to top, a GaAs substrate, a GaAs buffer layer, and a GaAs layer. 0.51 In 0.49 P-transition layer, Al 0.5 In 0.5 P-lower confinement layer, (Al) x1 Ga 1-x1 ) y1 In 1-y1 P-waveguide layer, (Al) x2 Ga 1-x2 ) y2 In 1-y2 P-bottom barrier, Ga 1-x3 In x3 P first quantum well, (Al) x4 Ga 1-x4 ) y3 In 1-y3 P barrier layer, Ga 1-x5 In x5 P second quantum well, (Al) x6 Ga 1-x6 ) y4 In 1-y4 P upper barrier layer, (Al) x7 Ga 1-x7 ) y5 In 1-y5 P upper waveguide layer, first Al 0.5 In 0.5 P-confinement layer, Ga 0.55 In 0.45 P corrosion termination layer, second Al 0.5 In 0.5 P-confinement layer, Ga 0.51 In 0.49 P-transition layer and GaAs cap layer; Wherein, 0.5≤x2≤0.7, 0.5≤y2≤0.65; 0.3≤x3≤0.5; 0.5≤x4≤0.7, 0.5≤y3≤0.65; 0.3≤x5≤0.5; 0.5≤x6≤0.7, 0.5≤y4≤0.65; (Al) x1 Ga1-x1 ) y1 In 1-y1 In the lower waveguide layer P, the x1 component gradually changes, and the range of x1 component change is between 1 and 0.4, while the y1 component remains unchanged, with 0.4≤y1≤0.6; (Al) x7 Ga 1-x7 ) y5 In 1-y5 In the waveguide layer on P, the x7 component is gradually varied, with the variation range of x7 being between 0.4 and 1. The y5 component remains unchanged, with 0.4 ≤ y5 ≤ 0.6. The x1 component is gradually varied while the y1 component remains unchanged, and the x7 component is gradually varied while the y5 component remains unchanged. This gradually varied structure design improves the carrier collection capability and reduces the voltage rise caused by the barrier height.

[0008] x2 is greater than the final value of the x1 component gradient, and x6 is greater than the initial value of the x7 component gradient, thus reducing (Al). x2 Ga 1-x2 ) y2 In 1-y2 P lower barrier and (Al) x6 Ga 1-x6 ) y4 In 1-y4 The refractive index of the upper barrier layer of P causes the light emitted from the quantum well to extend to the upper and lower waveguide layers on both sides. At this time, the waveguide layer is thinner and has poor confinement ability. Part of the light field extends into the confinement layer, the near-field light spot increases, thereby reducing the far-field light spot and promoting the extension of the light field.

[0009] The values ​​of y2 and y4 are greater than or equal to 0.5, representing the tensile strain of the barrier layer. Combined with the compressive strain compensation of the quantum well, this reduces strain accumulation in the active region.

[0010] According to a preferred embodiment of the present invention, the (Al) x7 Ga 1-x7 ) y5 In 1-y5 The thickness of the waveguide layer on P is 15-50nm, and it is not intentionally doped. Further optimized, x7 gradually changes from 0.45 to 0.95, y5 = 0.5, (Al) x7 Ga 1-x7 ) y5 In 1-y5 The thickness of the waveguide layer on P is 35 nm. An extremely narrow waveguide layer is used to reduce the optical field confinement, expand the vertical optical field, and decrease the far-field divergence angle.

[0011] According to a preferred embodiment of the present invention, the (Al) 1-x1 Ga x1 ) y1 In 1-y1 The thickness of the waveguide layer under P is 15-50nm, and it is not intentionally doped. Further optimized, x1 gradually changes from 0.95 to 0.45, y1=0.5, (Al) 1-x1 Ga x1 ) y1 In 1-y1 The thickness of the lower waveguide layer is 35 nm. Traditionally, the thickness of the upper and lower waveguide layers is usually 50-100 nm, or 1 μm for large optical cavity structures, which improves the optical field confinement capability and confines the optical field within the active region composed of the waveguide layer and quantum well. However, this invention uses an extremely narrow waveguide layer, which reduces the optical field confinement capability, allows the optical field to diffuse to the confinement layer, expands the optical field in the vertical direction, and reduces the far-field divergence angle.

[0012] A method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer includes the following steps: S1. Place the GaAs substrate in the growth chamber of the MOCVD equipment, heat the H2 environment to 720±10℃ for baking, and introduce AsH3 to perform surface heat treatment on the GaAs substrate. S2, the temperature is slowly reduced to 680±10℃, with a cooling rate not exceeding 30℃ / min. TMGa and AsH3 are continued to be introduced to grow a GaAs buffer layer on the GaAs substrate. The purpose is to prevent defects from spreading from the substrate into the confinement layer, provide a fresh growth interface, and improve the material growth quality. S3, the temperature is maintained at 680±10℃, which stops the growth on the GaAs buffer layer. PH3 is introduced to stop the growth by stopping the V group source (100% AsH3) and the III group source (TMGa). The stoppage lasts for 3 to 30 seconds, exhausting the As atoms in the reaction chamber. S4, with the temperature maintained at 680±10℃, TMGa, TMIn, and PH3 are introduced to grow Ga on the GaAs buffer layer. 0.51 In 0.49 The purpose of the lower transition layer is to reduce the band gap abrupt change and improve the electron migration rate; S5, the temperature is gradually increased to 700±10℃, with a heating rate not exceeding 60℃ / min, and TMAl, TMIn, and PH3 are introduced into the Ga... 0.51 In 0.49 n-type Al grows on the lower transition layer of P. 0.5 In 0.5 P-level confinement layer; S6, the temperature is gradually reduced to 650±10℃, and TMAl, TMIn, TMGa and PH3 are introduced, in Al 0.5 In 0.5 Growth on the P-limiting layer (Al) x1 Ga 1-x1 ) y1 In 1-y1In the lower waveguide layer of P, by changing the flow rates of TMAl and TMGa while keeping the flow rate of TMIn constant, the Al composition is gradually changed. The gradual bandgap helps to improve the carrier injection efficiency and enhance the photoelectric conversion efficiency. S7, temperature maintained at 650±10℃, TMAl, TMIn, TMGa and PH3 are introduced, and growth (Al) is carried out on the lower waveguide layer. x2 Ga 1-x2 ) y2 In 1-y2 In the lower barrier layer P, the Al component is greater than the gradually decreasing value of x1 in the lower waveguide layer. At the same time, tensile strain compensation is used to reduce the refractive index of the barrier and promote the spread of the optical field. S8, the temperature is maintained at 650±10℃, and TMI, TMGa, and PH3 are continuously introduced into the solution. x2 Ga 1-x2 ) y2 In 1-y2 Ga grows on the lower barrier layer of P. 1-x3 In x3 P-first quantum well; S9, the temperature is maintained at 650±10℃, and TMAl, TMIn, TMGa and PH3 are introduced, in which Ga 1-x3 In x3 Growth on the first quantum well (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-barrier layer; S10, the temperature is maintained at 650±10℃, and TMI, TMGa, and PH3 are continuously introduced, in the (Al) x4 Ga 1-x4 ) y3 In 1- y3 Ga grows on the P barrier layer 1-x5 In x5 P-second quantum well; S11, the temperature is gradually reduced to 700±10℃, and TMAl, TMIn, TMGa and PH3 are introduced. 1-x5 In x5 Growth on the second quantum well (Al) x6 Ga 1-x6 ) y4 In 1-y4 The upper barrier layer has an Al composition greater than the initial value of x7 gradient in the upper waveguide layer. At the same time, tensile strain compensation is used to reduce the refractive index of the barrier and promote the spread of the optical field. S12, the temperature is maintained at 700±10℃, and TMAl, TMIn, TMGa and PH3 are introduced to grow (Al) on the upper barrier layer. x7 Ga1-x7 ) y5 In 1-y5 By changing the flow rates of TMAl and TMGa while keeping the flow rate of TMIn constant, the Al composition can be gradually varied in the waveguide layer on P. This gradual bandgap variation helps to improve carrier injection efficiency and enhance photoelectric conversion efficiency. S13, with the temperature maintained at 700±10℃, TMA1, TMI, and PH3 are continuously introduced to grow a P-type first Al on the upper waveguide layer. 0.5 In 0.5 P is a confinement layer; S14, the temperature is maintained at 700±10℃, and TMGa, TMIn and PH3 are continuously introduced into the first Al... 0.5 In 0.5 P-type Ga is grown on the P-confinement layer. 0.55 In 0.45 P-corrosion termination layer; S15, with the temperature maintained at 700±10℃, TMAl, TMIn, and PH3 are continuously introduced to grow a P-type second Al on the corrosion termination layer. 0.5 In 0.5 P is a confinement layer; S16, the temperature is gradually increased to 680±10℃, and TMI, TMGa, and PH3 are introduced into the second Al... 0.5 In 0.5 Ga is grown on P-confinement layer 0.51 In 0.49 P-transition layer; S17, the temperature is reduced to 540±10℃, the cooling rate is not more than 40℃ / min, and TMGa and AsH3 are continued to be introduced to grow a GaAs cap layer on the upper transition layer.

[0013] According to a preferred embodiment of the present invention, in step S2, the doping source of the GaAs buffer layer is Si2H6, and the doping concentration is 2E18-5E18 atoms / cm³. 3 The thickness is 0.1-0.3 μm; more preferably, the GaAs buffer layer has a thickness of 0.2 μm and a doping concentration of 2E18 atoms / cm. 3 .

[0014] According to a preferred embodiment of the present invention, in step S4, the Ga 0.51 In 0.49 The doping source for the transition layer under P is Si₂H₆, with a doping concentration of 2E¹⁸-5E¹⁸ atoms / cm². 3 The thickness is 0.1-0.3 μm; more preferably, Ga 0.51 In 0.49 The thickness of the transition layer under P is 0.2 μm, and the doping concentration is 4E18 atoms / cm.3 .

[0015] According to a preferred embodiment of the present invention, in step S5, the Al 0.5 In 0.5 The doping source for the lower confinement layer is Si₂H₆, with a doping concentration of 7E¹⁷-2E¹⁸ atoms / cm². 3 The thickness is 0.5-1 μm; more preferably, Al 0.5 In 0.5 The thickness of the P-type confinement layer is 0.9 μm, and the doping concentration is 1E¹⁸ atoms / cm². 3 .

[0016] According to a preferred embodiment of the present invention, in step S6, the (Al) 1-x1 Ga x1 ) y1 In 1-y1 The thickness of the waveguide layer under P is 15-50 nm, unintentionally doped, with 0.4 ≤ x1 ≤ 1 and 0.4 ≤ y1 ≤ 0.6; more preferably, x1 gradually changes from 0.95 to 0.45, y1 = 0.5, (Al 1-x1 Ga x1 ) y1 In 1-y1 The thickness of the P-waveguide layer is 35nm. An extremely narrow waveguide layer is used to reduce the optical field confinement capability, expand the vertical optical field, and reduce the far-field divergence angle.

[0017] According to a preferred embodiment of the present invention, in step S7, the (Al) x2 Ga 1-x2 ) y2 In 1-y2 The thickness of the barrier layer under P is 4-7 nm, unintentionally doped, with 0.5 ≤ x² ≤ 0.7 and 0.5 ≤ y² ≤ 0.65; more preferably, (Al) x2 Ga 1-x2 ) y2 In 1-y2 The thickness of the barrier layer under P is 5nm, x2=0.55, the value is greater than x1 and the value is 0.45 at the end, which reduces the refractive index of the barrier and promotes the spread of the optical field. y2=0.55, tensile strain compensation, reduces stress accumulation in the active region and improves long-term reliability.

[0018] According to a preferred embodiment of the present invention, in step S8, the Ga 1-x3 In x3 The thickness of the first quantum well (P) is 4-7 nm, unintentionally doped, with a strength of 0.3 ≤ x3 ≤ 0.5, and subjected to compressive strain; more preferably, x3 = 0.4, Ga 1-x3 In x3 The thickness of the first quantum well is 5 nm.

[0019] According to a preferred embodiment of the present invention, in step S9, the (Al) x4 Ga 1-x4 ) y3 In 1-y3 The thickness of the P-barrier layer is 5-15 nm, unintentionally doped, with 0.5 ≤ x4 ≤ 0.7, 0.5 ≤ y3 ≤ 0.65, and subjected to tensile strain; more preferably, x4 = 0.55, y3 = 0.55, (Al x4 Ga 1-x4 ) y3 In 1-y3 The thickness of the P-barrier layer is 5 nm.

[0020] According to a preferred embodiment of the present invention, in step S10, the Ga 1-x5 In x5 The thickness of the second quantum well (P) is 4-7 nm, unintentionally doped, with a strength of 0.3 ≤ x5 ≤ 0.5, and subjected to compressive strain; more preferably, x5 = 0.4, Ga 1-x5 In x5 The thickness of the second quantum well is 5 nm.

[0021] According to a preferred embodiment of the present invention, in step S11, the (Al) x6 Ga 1-x6 ) y4 In 1-y4 The thickness of the barrier layer on P is 4-7 nm, unintentionally doped, with 0.5 ≤ x6 ≤ 0.7 and 0.5 ≤ y4 ≤ 0.65; more preferably, (Al) x6 Ga 1-x6 ) y4 In 1-y4 The thickness of the barrier layer on P is 5nm, x6=0.55, which is greater than the initial value of x7 (0.45) to reduce the refractive index of the barrier and promote the spread of the optical field. y4=0.55 is used for tensile strain compensation to reduce stress accumulation in the active region and improve long-term operational reliability.

[0022] According to a preferred embodiment of the present invention, in step S12, the (Al) x7 Ga 1-x7 ) y5 In 1-y5 The thickness of the waveguide layer on P is 15-50 nm, unintentionally doped, with 0.4 ≤ x7 ≤ 1 and 0.4 ≤ y5 ≤ 0.6; more preferably, x7 gradually changes from 0.45 to 0.95, y5 = 0.5, (Al x7 Ga 1-x7 ) y5 In 1-y5 The thickness of the waveguide layer on P is 35nm. An extremely narrow waveguide layer is used to reduce the optical field confinement capability, expand the optical field in the vertical direction, and reduce the far-field divergence angle.

[0023] According to a preferred embodiment of the present invention, in step S13, the first Al 0.5 In 0.5 The doping source for the confinement layer on P is Cp₂Mg, with a doping concentration of 3E¹⁷–1.2E¹⁸ atoms / cm². 3 The thickness is 0.1-0.3 μm; more preferably, Al 0.5 In 0.5 The thickness of the first upper confinement layer is 0.15 μm, and the doping concentration is 5E17 atoms / cm². 3 .

[0024] According to a preferred embodiment of the present invention, in step S14, the Ga 0.51 In 0.49 The doping source for the P-etch termination layer is Cp₂Mg, with a doping concentration of 5E¹⁷-2E¹⁸ atoms / cm². 3 The thickness is 5-20 nm; more preferably, Ga 0.51 In 0.49 The thickness of the P-etching termination layer is 10 nm, and the doping concentration is 1 E18 atoms / cm. 3 .

[0025] According to a preferred embodiment of the present invention, in step S15, the second Al 0.5 In 0.5 The doping source for the confinement layer on P is Cp₂Mg, with a doping concentration of 3E¹⁷–1.2E¹⁸ atoms / cm². 3 The thickness is 0.5-1.2 μm; more preferably, the second Al 0.5 In 0.5 The thickness of the confinement layer on P is 0.7 μm, and the doping concentration is 7E17 atoms / cm. 3 .

[0026] According to a preferred embodiment of the present invention, in step S16, the Ga 0.51 In 0.49 The doping source for the transition layer on P is Cp₂Mg, with a doping concentration of 1.5E¹⁸-3E¹⁸ atoms / cm². 3 The thickness is 20-40 nm; more preferably, Ga 0.5 In 0.5 The thickness of the transition layer on P is 24 nm, and the doping concentration is 2 E18 atoms / cm. 3 .

[0027] According to a preferred embodiment of the present invention, in step S17, the thickness of the GaAs cap layer is 0.1-0.5 μm, the doping source is CBr4 or DEZn, and the doping concentration is 4E19-1E20 atoms / cm². 3Further preferably, the GaAs cap layer has a thickness of 0.2 μm and a doping concentration of 7E19 atoms / cm². 3 .

[0028] The beneficial effects of this invention are as follows: 1. By inserting a low-refractive-index barrier layer between the waveguide layer and the quantum well, the refractive index of the barrier is reduced, which promotes the expansion of the optical field and reduces the far-field beam divergence angle. At the same time, tensile strain compensation is used to reduce stress accumulation in the active region.

[0029] 2. By adopting a narrow waveguide structure, the optical field confinement capability is reduced, and part of the optical field is extended into the confinement layer, thus expanding the vertical optical field and reducing the far-field divergence angle. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the laser device described in this invention; Figure 2 This is a schematic diagram of the structure of a conventional laser device; Figure 3 This is a schematic diagram of the divergence angle test results of the laser device described in this invention; Figure 4 This is a schematic diagram of the divergence angle test results after coating a conventional structure with a cavity length of 300μm and a strip width of 4μm.

[0031] 1. GaAs substrate, 2. GaAs buffer layer, 3. Ga 0.51 In 0.49 P-transition layer, 4, Al 0.5 In 0.5 P-lower confinement layer, 5, (Al) x1 Ga 1-x1 ) y1 In 1-y1 P-waveguide layer, 6, (Al) x2 Ga 1-x2 ) y2 In 1-y2 P-base layer, 7, Ga 1-x3 In x3 P first quantum well, 8, (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-barrier layer, 9, Ga 1-x5 In x5 P second quantum well, 10, (Al) x6 Ga 1-x6 ) y4 In 1-y4 P upper layer, 11, (Al) x7 Ga 1-x7 ) y5 In1-y5 P-waveguide layer, 12, first Al 0.5 In 0.5 P upper confinement layer, 13, Ga 0.55 In 0.45 P corrosion termination layer, 14, second Al 0.5 In 0.5 P-confinement layer, 15, Ga 0.51 In 0.49 P is a transition layer, and 16 is a GaAs cap layer. Detailed Implementation

[0032] The present invention will be further described below with reference to the embodiments and accompanying drawings, but is not limited thereto.

[0033] Example 1 A narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer includes, from bottom to top, a GaAs substrate 1, a GaAs buffer layer 2, and a GaAs layer 3. 0.51 In 0.49 P-transition layer 3, Al 0.5 In 0.5 P-lower confinement layer 4, (Al) x1 Ga 1-x1 ) y1 In 1- y1 P-waveguide layer 5, (Al) x2 Ga 1-x2 ) y2 In 1-y2 P lower barrier layer 6, Ga 1-x3 In x3 P first quantum well 7, (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-barrier layer 8, Ga 1-x5 In x5 P second quantum well 9, (Al) x6 Ga 1-x6 ) y4 In 1-y4 P upper base layer 10, (Al) x7 Ga 1-x7 ) y5 In 1-y5 P upper waveguide layer 11, first Al 0.5 In 0.5 P upper confinement layer 12, Ga 0.55 In 0.45 P corrosion termination layer 13, second Al 0.5 In 0.5 P upper confinement layer 14, Ga 0.51 In0.49 P-transition layer 15 and GaAs cap layer 16; Wherein, 0.5≤x2≤0.7, 0.5≤y2≤0.65; 0.3≤x3≤0.5; 0.5≤x4≤0.7, 0.5≤y3≤0.65; 0.3≤x5≤0.5; 0.5≤x6≤0.7, 0.5≤y4≤0.65; (Al) x1 Ga 1-x1 ) y1 In 1-y1 In waveguide layer 5 below P, the x1 component gradually changes, and the range of x1 component change is between 1 and 0.4, while the y1 component remains unchanged, with 0.4≤y1≤0.6; (Al) x7 Ga 1-x7 ) y5 In 1-y5 In waveguide layer 11 on P, the x7 component is gradually varied, with the variation range of x7 being between 0.4 and 1. The y5 component remains unchanged, with 0.4 ≤ y5 ≤ 0.6. The x1 component is gradually varied while the y1 component remains unchanged, and the x7 component is gradually varied while the y5 component remains unchanged. This gradually varied structure design improves the carrier collection capability and reduces the voltage rise caused by the barrier height.

[0034] x2 is greater than the final value of the x1 component gradient, and x6 is greater than the initial value of the x7 component gradient, which reduces the refractive index of the potential barrier and promotes the expansion of the light field.

[0035] The values ​​of y2 and y4 are greater than 0.5, representing the tensile strain of the barrier layer. Combined with the compressive strain compensation of the quantum well, this reduces strain accumulation in the active region.

[0036] (Al) x7 Ga 1-x7 ) y5 In 1-y5 The thickness of waveguide layer 11 on P is 15-50nm, and it is not intentionally doped; By employing an extremely narrow waveguide layer, the optical field confinement capability is reduced, the vertical optical field is expanded, and the far-field divergence angle is decreased.

[0037] (Al) 1-x1 Ga x1 ) y1 In 1-y1 The thickness of waveguide layer 5 under P is 15-50nm, and it is not intentionally doped.

[0038] Example 2 Example 1 provides a method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer, comprising the following steps: S1. Place GaAs substrate 1 in the growth chamber of the MOCVD equipment, heat the H2 environment to 720±10℃ for baking, and introduce AsH3 to perform surface heat treatment on GaAs substrate 1. S2, the temperature is slowly reduced to 680±10℃, and the cooling rate is no higher than 30℃ / min. TMGa and AsH3 are continued to be introduced to grow GaAs buffer layer 2 on GaAs substrate 1. The purpose is to prevent defects from spreading from the substrate into the confinement layer, provide a fresh growth interface, and improve the material growth quality. In step S2, the doping source for GaAs buffer layer 2 is Si2H6, and the doping concentration is 2E18-5E18 atoms / cm³. 3 The thickness is 0.1-0.3μm.

[0039] S3, the temperature is maintained at 680±10℃, which stops the growth on GaAs buffer layer 2. PH3 is introduced to stop the growth by stopping the V group source (100% AsH3) and the III group source (TMGa). The stoppage lasts for 3s to 30s, exhausting the As atoms in the reaction chamber. S4, with the temperature maintained at 680±10℃, TMGa, TMIn, and PH3 are introduced to grow Ga on GaAs buffer layer 2. 0.51 In 0.49 The purpose of the P-transition layer 3 is to reduce the band gap abrupt change and improve the electron migration rate; In step S4, Ga 0.51 In 0.49 The doping source for the lower transition layer 3 is Si₂H₆, with a doping concentration of 2E¹⁸-5E¹⁸ atoms / cm². 3 The thickness is 0.1-0.3μm.

[0040] S5, temperature gradually decreases to 700±10℃, heating rate not exceeding 60℃ / min, TMAl, TMIn and PH3 are introduced, in Ga 0.51 In 0.49 n-type Al grows on the lower transition layer 3 of P. 0.5 In 0.5 P-lower confinement layer 4; Al 0.5 In 0.5 The doping source for the lower confinement layer 4 is Si₂H₆, with a doping concentration of 7E¹⁷-2E¹⁸ atoms / cm². 3 The thickness is 0.5-1μm.

[0041] S6, the temperature is gradually reduced to 650±10℃, and TMAl, TMIn, TMGa and PH3 are introduced, in Al 0.5 In 0.5 Growth on P-restricted layer 4 (Al) x1 Ga1-x1 ) y1 In 1-y1 In the lower waveguide layer 5 of P, by changing the flow rates of TMAl and TMGa while keeping the flow rate of TMIn constant, the Al composition is gradually changed. The gradual change of bandgap helps to improve the carrier injection efficiency and enhance the photoelectric conversion efficiency. (Al) 1-x1 Ga x1 ) y1 In 1-y1 The thickness of waveguide layer 5 under P is 15-50nm, unintentionally doped, 0.4≤x1≤1, 0.4≤y1≤0.6; an extremely narrow waveguide layer is used to reduce the optical field confinement capability, expand the optical field in the vertical direction, and reduce the far-field divergence angle.

[0042] S7, with the temperature maintained at 650±10℃, is grown on the lower waveguide layer 5 by introducing TMAl, TMIn, TMGa, and PH3. (Al) x2 Ga 1-x2 ) y2 In 1-y2 The lower barrier layer 6 has an Al composition greater than the lower waveguide layer 5x1, which is gradually reduced to a final value. At the same time, tensile strain compensation is used to reduce the refractive index of the barrier and promote the spread of the optical field. (Al) x2 Ga 1-x2 ) y2 In 1-y2 The thickness of the P-barrier layer 6 is 4-7 nm, unintentionally doped, with 0.5 ≤ x2 ≤ 0.7 and 0.5 ≤ y2 ≤ 0.65.

[0043] S8, temperature maintained at 650±10℃, TMI, TMGa and PH3 are continuously introduced, in (Al) x2 Ga 1-x2 ) y2 In 1-y2 Ga is grown on the lower barrier layer 6 of P. 1-x3 In x3 P first quantum well 7; Ga 1-x3 In x3 The thickness of the first quantum well 7 is 4-7 nm, unintentionally doped, 0.3 ≤ x3 ≤ 0.5, and subjected to compressive strain.

[0044] S9, temperature maintained at 650±10℃, TMAl, TMIn, TMGa and PH3 are introduced, in Ga 1-x3 In x3 Growth on the first quantum well 7 (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-layer 8; (Al)x4 Ga 1-x4 ) y3 In 1-y3 The thickness of the P-barrier layer 8 is 5-15 nm, unintentionally doped, with 0.5≤x4≤0.7 and 0.5≤y3≤0.65, and subjected to tensile strain.

[0045] S10, temperature maintained at 650±10℃, TMI, TMGa and PH3 are continuously introduced, in (Al) x4 Ga 1-x4 ) y3 In 1-y3 Ga is grown on the P-barrier layer 8 1-x5 In x5 P second quantum well 9; Ga 1-x5 In x5 The thickness of the second quantum well 9 is 4-7 nm, unintentionally doped, 0.3 ≤ x5 ≤ 0.5, and subjected to compressive strain.

[0046] S11, the temperature is gradually reduced to 700±10℃, and TMAl, TMIn, TMGa and PH3 are introduced, in Ga 1-x5 In x5 Growth on the second quantum well 9 (Al) x6 Ga 1-x6 ) y4 In 1-y4 The upper barrier layer is 10, and the Al composition is greater than the initial value of the upper waveguide layer x7. At the same time, tensile strain compensation is used to reduce the refractive index of the barrier and promote the spread of the optical field. (Al) x6 Ga 1-x6 ) y4 In 1-y4 The thickness of the barrier layer 10 on P is 4-7 nm, unintentionally doped, with 0.5 ≤ x6 ≤ 0.7 and 0.5 ≤ y4 ≤ 0.65.

[0047] S12, temperature maintained at 700±10℃, TMAl, TMIn, TMGa and PH3 are introduced, and growth (Al) is carried out on the upper barrier layer. x7 Ga 1-x7 ) y5 In 1-y5 The waveguide layer 11 on P achieves a gradual change in Al composition by changing the flow rates of TMAl and TMGa while keeping the flow rate of TMIn constant. This gradual change in bandgap helps to improve carrier injection efficiency and enhance photoelectric conversion efficiency. (Al) x7 Ga 1-x7 ) y5 In 1-y5The thickness of waveguide layer 11 on P is 15-50nm, unintentionally doped, 0.4≤x7≤1, 0.4≤y5≤0.6; an extremely narrow waveguide layer is used to reduce the optical field confinement capability, expand the optical field in the vertical direction, and reduce the far-field divergence angle.

[0048] S13, with the temperature maintained at 700±10℃, continues to introduce TMAl, TMIn, and PH3 to grow P-type first Al on the upper waveguide layer. 0.5 In 0.5 P is restricted by layer 12; First Al 0.5 In 0.5 The doping source for the confinement layer 12 on P is Cp₂Mg, with a doping concentration of 3E¹⁷-1.2E¹⁸ atoms / cm². 3 The thickness is 0.1-0.3μm.

[0049] S14, the temperature is maintained at 700±10℃, and TMGa, TMI, and PH3 are continuously introduced into the first Al. 0.5 In 0.5 P-type Ga is grown on the upper confinement layer 12. 0.55 In 0.45 P-corrosion termination layer 13; Ga 0.51 In 0.49 The doping source for the P-etch termination layer 13 is Cp₂Mg, with a doping concentration of 5E¹⁷-2E¹⁸ atoms / cm². 3 The thickness is 5-20nm.

[0050] S15, with the temperature maintained at 700±10℃, continues to introduce TMAl, TMIn, and PH3 to grow a P-type second Al on the corrosion termination layer. 0.5 In 0.5 P is restricted by layer 14; Second Al 0.5 In 0.5 The doping source for the confinement layer 14 on P is Cp₂Mg, with a doping concentration of 3E¹⁷–1.2E¹⁸ atoms / cm². 3 The thickness is 0.5-1.2μm.

[0051] S16, temperature gradually increased to 680±10℃, TMI, TMGa and PH3 were introduced, in the second Al 0.5 In 0.5 Ga is grown on the confinement layer 14 of P. 0.51 In 0.49 P upper transition layer 15; Ga 0.51 In 0.49 The doping source for the transition layer 15 on P is Cp₂Mg, with a doping concentration of 1.5E¹⁸-3E¹⁸ atoms / cm².3 The thickness is 20-40nm.

[0052] S17, the temperature is reduced to 540±10℃, the cooling rate is not more than 40℃ / min, and TMGa and AsH3 are continued to be introduced to grow a GaAs cap layer 16 on the upper transition layer.

[0053] The GaAs cap layer 16 has a thickness of 0.1-0.5 μm, and the doping source is CBr4 or DEZn, with a doping concentration of 4E19-1E20 atoms / cm². 3 .

[0054] The MOCVD equipment and other technologies used in the method of this invention are all existing technologies.

[0055] TMGa, TMIn, TMAl, PH3, and AsH3 are all raw materials for MOCVD epitaxial growth, while Si2H6, Cp2Mg, CBr4, and DEZn are all dopant sources for epitaxial growth.

[0056] Among them, the GaAs substrate 1 has an offset angle of 6-15°.

[0057] Example 3 The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer differs from Example 2 in that: In step S2, the thickness of GaAs buffer layer 2 is 0.2 μm, and the doping concentration is 2E18 atoms / cm². 3 .

[0058] In step S4, Ga is further preferred. 0.51 In 0.49 The thickness of the P-transition layer 3 is 0.2 μm, and the doping concentration is 4E18 atoms / cm². 3 .

[0059] In step S5, Al 0.5 In 0.5 The thickness of the P-confinement layer 4 is 0.9 μm, and the doping concentration is 1E18 atoms / cm². 3 .

[0060] In step S6, x1 gradually changes from 0.95 to 0.45, y1 = 0.5, (Al) 1-x1 Ga x1 ) y1 In 1-y1 The thickness of waveguide layer 5 under P is 35nm. It adopts an extremely narrow waveguide layer to reduce the optical field confinement capability, expand the optical field in the vertical direction, and reduce the far-field divergence angle.

[0061] In step S7, (Al) x2 Ga 1-x2) y2 In 1-y2 The thickness of the lower barrier layer 6 is 5nm, x2=0.55, the value is greater than x1 and the value is 0.45 at the end, which reduces the refractive index of the barrier and promotes the expansion of the optical field. y2=0.55, tensile strain compensation, reduces stress accumulation in the active region and improves long-term reliability.

[0062] In step S8, x3 = 0.4, Ga 1-x3 In x3 The thickness of the first quantum well 7 is 5 nm.

[0063] In step S9, x4 = 0.55, y3 = 0.55, (Al) x4 Ga 1-x4 ) y3 In 1-y3 The thickness of the P-barrier layer 8 is 5 nm.

[0064] In step S10, x5 = 0.4, Ga 1-x5 In x5 The thickness of the second quantum well 9 is 5 nm.

[0065] In step S11, (Al) x6 Ga 1-x6 ) y4 In 1-y4 The thickness of the barrier layer 10 on P is 5nm, x6=0.55, which is greater than the initial value of x7 of 0.45, to reduce the refractive index of the barrier and promote the spread of the optical field. y4=0.55, tensile strain compensation, reduces stress accumulation in the active region and improves long-term reliability.

[0066] In step S12, x7 gradually changes from 0.45 to 0.95, y5 = 0.5, (Al) x7 Ga 1-x7 ) y5 In 1-y5 The thickness of waveguide layer 11 on P is 35nm. It adopts an extremely narrow waveguide layer to reduce the optical field confinement capability, expand the optical field in the vertical direction, and reduce the far-field divergence angle.

[0067] In step S13, Al 0.5 In 0.5 The thickness of the first upper confinement layer 12 is 0.15 μm, and the doping concentration is 5E17 atoms / cm. 3 .

[0068] In step S14, Ga 0.51 In 0.49 The thickness of the P-etching termination layer 13 is 10 nm, and the doping concentration is 1 E18 atoms / cm. 3 .

[0069] In step S15, the second Al 0.5 In 0.5 The thickness of the confinement layer 14 on P is 0.7 μm, and the doping concentration is 7E17 atoms / cm. 3 .

[0070] In step S16, Ga 0.5 In 0.5 The thickness of the transition layer 15 on P is 24 nm, and the doping concentration is 2 E18 atoms / cm. 3 .

[0071] In step S17, the GaAs cap layer 16 has a thickness of 0.2 μm and a doping concentration of 7E19 atoms / cm². 3 .

[0072] like Figure 1 and Figure 2 As shown in the diagram, the comparative structure reveals that this invention achieves its effect by inserting a low-refractive-index barrier layer between the waveguide layer and the quantum well, i.e., (Al... x6 Ga 1-x6 ) y4 In 1-y4 The P-layer 10 lowers the refractive index of the barrier, while the narrow waveguide structure helps to expand the optical field and reduce the vertical divergence angle.

[0073] Figure 3 This is a divergence angle test of the structure of the laser device of the present invention. Figure 4 The divergence angle of a conventional structure with a cavity length of 300μm and a stripe width of 4μm after coating is measured, where the vertical axis is the light intensity and the horizontal axis is the test angle at half the light intensity. The comparison results show that the horizontal divergence angle and vertical divergence angle of the laser device of the present invention are 7.6° and 24.2°, respectively, while the horizontal divergence angle and vertical divergence angle of the conventional structure are 7.7° and 33.8°, respectively. It can be seen that the present invention inserts a low refractive index barrier layer and adopts a narrow waveguide structure, which expands the longitudinal optical field. While the horizontal divergence angle is basically the same, the vertical divergence angle is greatly reduced.

Claims

1. A narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer, characterized in that, Includes, from bottom to top, a GaAs substrate, a GaAs buffer layer, and a GaAs layer. 0.51 In 0.49 P-transition layer, Al 0.5 In 0.5 P-lower confinement layer, (Al) x1 Ga 1-x1 ) y1 In 1-y1 P-waveguide layer, (Al) x2 Ga 1-x2 ) y2 In 1-y2 P-bottom barrier, Ga 1-x3 In x3 P first quantum well, (Al) x4 Ga 1-x4 ) y3 In 1-y3 P barrier layer, Ga 1-x5 In x5 P second quantum well, (Al) x6 Ga 1-x6 ) y4 In 1-y4 P upper barrier layer, (Al) x7 Ga 1-x7 ) y5 In 1-y5 P upper waveguide layer, first Al 0.5 In 0.5 P-confinement layer, Ga 0.55 In 0.45 P corrosion termination layer, second Al 0.5 In 0.5 P-confinement layer, Ga 0.51 In 0.49 P-transition layer and GaAs cap layer; Wherein, 0.5≤x2≤0.7, 0.5≤y2≤0.65; 0.3≤x3≤0.5; 0.5≤x4≤0.7, 0.5≤y3≤0.65; 0.3≤x5≤0.5; 0.5≤x6≤0.7, 0.5≤y4≤0.65; (Al) x1 Ga 1-x1 ) y1 In 1-y1 In the lower waveguide layer P, the x1 component gradually changes, and the range of x1 component change is between 1 and 0.4, while the y1 component remains unchanged, with 0.4≤y1≤0.6; (Al) x7 Ga 1-x7 ) y5 In 1-y5 In the waveguide layer on P, the x7 component gradually changes, and the range of x7 component change is between 0.4 and 1, while the y5 component remains unchanged, with 0.4≤y5≤0.6; x2 is greater than the final value of the x1 component gradient, and x6 is greater than the initial value of the x7 component gradient.

2. The narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 1, characterized in that, The (Al) x7 Ga 1-x7 ) y5 In 1-y5 The thickness of the waveguide layer on P is 15-50 nm, and it is not intentionally doped.

3. The narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 2, characterized in that, x7 gradually changes from 0.45 to 0.95, y5 = 0.5, (Al) x7 Ga 1-x7 ) y5 In 1-y5 The thickness of the waveguide layer on P is 35 nm.

4. The narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 1, characterized in that, The (Al) 1-x1 Ga x1 ) y1 In 1-y1 The thickness of the waveguide layer under P is 15-50nm, and it is not intentionally doped.

5. A narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 4, characterized in that, x1 gradually changes from 0.95 to 0.45, y1 = 0.5, (Al) 1-x1 Ga x1 ) y1 In 1-y1 The thickness of the waveguide layer under P is 35 nm.

6. A method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Place the GaAs substrate in the growth chamber of the MOCVD equipment, heat the H2 environment to 720±10℃ for baking, and introduce AsH3 to perform surface heat treatment on the GaAs substrate. S2, the temperature is lowered to 680±10℃, and TMGa and AsH3 are continued to be introduced to grow a GaAs buffer layer on the GaAs substrate. S3, the temperature is maintained at 680±10℃, which stops the growth on the GaAs buffer layer. PH3 is introduced to deplete the As atoms in the reaction chamber. S4, with the temperature maintained at 680±10℃, TMGa, TMIn, and PH3 are introduced to grow Ga on the GaAs buffer layer. 0.51 In 0.49 P-level transition layer; S5, the temperature is raised to 700±10℃, and TMAl, TMIn and PH3 are introduced into the Ga... 0.51 In 0.49 n-type Al grows on the lower transition layer of P. 0.5 In 0.5 P-level confinement layer; S6, the temperature drops to 650±10℃, TMAl, TMIn, TMGa and PH3 are introduced, in Al 0.5 In 0.5 Growth on the P-limiting layer (Al) x1 Ga 1-x1 ) y1 In 1-y1 P-below waveguide layer; S7, temperature maintained at 650±10℃, TMAl, TMIn, TMGa and PH3 are introduced, and growth (Al) is carried out on the lower waveguide layer. x2 Ga 1-x2 ) y2 In 1-y2 P-base layer; S8, the temperature is maintained at 650±10℃, and TMI, TMGa, and PH3 are continuously introduced into the solution. x2 Ga 1-x2 ) y2 In 1-y2 Ga grows on the lower barrier layer of P. 1-x3 In x3 P-first quantum well; S9, the temperature is maintained at 650±10℃, and TMAl, TMIn, TMGa and PH3 are introduced, in which Ga 1-x3 In x3 Growth on the first quantum well (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-barrier layer; S10, the temperature is maintained at 650±10℃, and TMI, TMGa, and PH3 are continuously introduced, in the (Al) x4 Ga 1-x4 ) y3 In 1-y3 Ga grows on the P barrier layer 1-x5 In x5 P-second quantum well; S11, the temperature is gradually reduced to 700±10℃, and TMAl, TMIn, TMGa and PH3 are introduced. 1-x5 In x5 Growth on the second quantum well (Al) x6 Ga 1-x6 ) y4 In 1-y4 P-base layer; S12, the temperature is maintained at 700±10℃, and TMAl, TMIn, TMGa and PH3 are introduced to grow (Al) on the upper barrier layer. x7 Ga 1-x7 ) y5 In 1-y5 By changing the flow rates of TMAl and TMGa while keeping the flow rate of TMIn constant, a gradual change in Al composition can be achieved in the waveguide layer on P. S13, with the temperature maintained at 700±10℃, TMA1, TMI, and PH3 are continuously introduced to grow a P-type first Al on the upper waveguide layer. 0.5 In 0.5 P is a confinement layer; S14, the temperature is maintained at 700±10℃, and TMGa, TMIn and PH3 are continuously introduced into the first Al... 0.5 In 0.5 P-type Ga is grown on the P-confinement layer. 0.55 In 0.45 P-corrosion termination layer; S15, with the temperature maintained at 700±10℃, TMAl, TMIn, and PH3 are continuously introduced to grow a P-type second Al on the corrosion termination layer. 0.5 In 0.5 P is a confinement layer; S16, the temperature is gradually increased to 680±10℃, and TMI, TMGa, and PH3 are introduced into the second Al... 0.5 In 0.5 Ga is grown on P-confinement layer 0.51 In 0.49 P-transition layer; S17, the temperature is reduced to 540±10℃, the cooling rate is not more than 40℃ / min, and TMGa and AsH3 are continued to be introduced to grow a GaAs cap layer on the upper transition layer.

7. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S2, the doping source of the GaAs buffer layer is Si2H6, and the doping concentration is 2E18-5E18 atoms / cm³. 3 The thickness is 0.1-0.3μm.

8. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 7, wherein the GaAs buffer layer has a thickness of 0.2μm and a doping concentration of 2E18 atoms / cm². 3 .

9. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S4, the Ga 0.51 In 0.49 The doping source for the transition layer under P is Si₂H₆, with a doping concentration of 2E¹⁸-5E¹⁸ atoms / cm². 3 The thickness is 0.1-0.3μm.

10. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 9, Ga 0.51 In 0.49 The thickness of the transition layer under P is 0.2 μm, and the doping concentration is 4E18 atoms / cm. 3 .

11. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S5, the Al 0.5 In 0.5 The doping source for the lower confinement layer is Si₂H₆, with a doping concentration of 7E¹⁷-2E¹⁸ atoms / cm². 3 The thickness is 0.5-1μm.

12. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 11, Al 0.5 In 0.5 The thickness of the P-type confinement layer is 0.9 μm, and the doping concentration is 1E¹⁸ atoms / cm². 3 .

13. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S7, the (Al) x2 Ga 1-x2 ) y2 In 1-y2 The thickness of the P-barrier layer is 4-7 nm, unintentionally doped, with 0.5 ≤ x² ≤ 0.7 and 0.5 ≤ y² ≤ 0.

65.

14. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 13, characterized in that, (Al) x2 Ga 1-x2 ) y2 In 1-y2 The thickness of the barrier layer under P is 5 nm, x2 = 0.

55.

15. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S8, the Ga 1-x3 In x3 The thickness of the first quantum well is 4-7 nm, unintentionally doped, 0.3 ≤ x3 ≤ 0.5, and subjected to compressive strain.

16. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 15, characterized in that, x3=0.4, Ga 1-x3 In x3 The thickness of the first quantum well is 5 nm.

17. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S9, the (Al) x4 Ga 1-x4 ) y3 In 1-y3 The thickness of the P barrier layer is 5-15 nm, unintentionally doped, with 0.5≤x4≤0.7 and 0.5≤y3≤0.65, and subjected to tensile strain.

18. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 17, characterized in that, x4=0.55, y3=0.55, (Al) x4 Ga 1-x4 ) y3 In 1-y3 The thickness of the P-barrier layer is 5 nm.

19. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S10, the Ga 1-x5 In x5 The thickness of the second quantum well is 4-7 nm, unintentionally doped, 0.3 ≤ x5 ≤ 0.5, and subjected to compressive strain.

20. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 19, characterized in that, x5=0.4, Ga 1-x5 In x5 The thickness of the second quantum well is 5 nm.

21. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S11, the (A1) x6 Ga 1-x6 ) y4 In 1-y4 The thickness of the barrier layer on P is 4-7 nm, unintentionally doped, with 0.5 ≤ x6 ≤ 0.7 and 0.5 ≤ y4 ≤ 0.

65.

22. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 21, characterized in that, (Al) x6 Ga 1-x6 ) y4 In 1-y4 The thickness of the barrier layer on P is 5nm, x6=0.55, and the value is greater than the initial value of x7 (0.45), y4=0.

55.

23. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S13, the first Al 0.5 In 0.5 The doping source for the confinement layer on P is Cp₂Mg, with a doping concentration of 3E¹⁷–1.2E¹⁸ atoms / cm². 3 The thickness is 0.1-0.3μm.

24. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 23, characterized in that, Al 0.5 In 0.5 The thickness of the first upper confinement layer is 0.15 μm, and the doping concentration is 5E17 atoms / cm². 3 .

25. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S14, the Ga 0.51 In 0.49 The doping source for the P-etch termination layer is Cp₂Mg, with a doping concentration of 5E¹⁷-2E¹⁸ atoms / cm². 3 The thickness is 5-20nm.

26. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 25, characterized in that, Ga 0.51 In 0.49 The thickness of the P-etching termination layer is 10 nm, and the doping concentration is 1 E18 atoms / cm. 3 .

27. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S15, the second Al 0.5 In 0.5 The doping source for the confinement layer on P is Cp₂Mg, with a doping concentration of 3E¹⁷–1.2E¹⁸ atoms / cm². 3 The thickness is 0.5-1.2μm.

28. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 27, characterized in that, Second Al 0.5 In 0.5 The thickness of the confinement layer on P is 0.7 μm, and the doping concentration is 7E17 atoms / cm. 3 .

29. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S16, the Ga 0.51 In 0.49 The doping source for the transition layer on P is Cp₂Mg, with a doping concentration of 1.5E¹⁸-3E¹⁸ atoms / cm². 3 The thickness is 20-40nm.

30. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 29, characterized in that, Ga 0.5 In 0.5 The thickness of the transition layer on P is 24 nm, and the doping concentration is 2 E18 atoms / cm. 3 .

31. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 6, characterized in that, In step S17, the thickness of the GaAs cap layer is 0.1-0.5 μm, the doping source is CBr4 or DEZn, and the doping concentration is 4E19-1E20 atoms / cm². 3 .

32. The method for fabricating a narrow waveguide 650nm semiconductor laser device with a low refractive index barrier layer according to claim 31, characterized in that, The GaAs cap layer has a thickness of 0.2 μm and a doping concentration of 7E19 atoms / cm². 3 .

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